I think "nightmare" is a bit sensational. The LHC's purpose is not to "find X" it is to take measurements over a novel range of conditions. The new data is what we're after.
"Nightmare" was how physicists themselves characterize the situation we are in, and have done for at least 15 years. Look at the 2007 article linked in the article above: https://www.science.org/doi/10.1126/science.315.5819.1657 Jonathan Ellis is on the record there describing the scenario we find ourselves in now as "the real five-star disaster". (you can get the full article by putting the link into scholar.google.…
The whole history of high energy physics is a back-and-forth between models and experiment. We get to a new energy level, try some things that the models are ambiguous about, and previously we've gotten new and interesting results that lead people to reshape models and make new predictions. That has not, generally, happened with the LHC. The frustrating limitations and inconsistencies of the standard model are the same as when we built it.
The problem is we spent a lot of money and time and focus on building a tool that has not actually moved us forward much. This happens from time to time - but it's bad! We have not made our series of scientific advances by getting lucky on a bunch of coin flips - we've been able to use previous experiments to design the next set of tools in ways that productively open up parts of the science we could not observe before. The fact that we seem to have failed to accomplish this with one of the largest, most expensive tools ever built calls into question the methods that led us to choose to build this tool instead of other possible ones.